The DateTimeFormatInfo.UniversalSortableDateTimePattern property defines the format of date strings that are returned by calls to the DateTime.ToString and DateTimeOffset.ToString methods and by composite format strings that are supplied the "u" standard format string. It can be used to display dates and times in a sortable order with the universal time designator "Z" at the end. The format is sortable because it uses leading zeros for year, month, day, hour, minute, and second. The custom format string ("yyyy'-'MM'-'dd HH':'mm':'ss'Z'") is the same regardless of culture or format provider.